Unfortunately, though, the change doesn't apply to plans that enroll some of the sickest people: those who buy coverage in so-called high-risk insurance pools because they have medical problems that make them uninsurable in the private market.

People in the pools are left out because of a wrinkle in legal language.

The law applies to health plans and health insurance issuers as defined by the Public Health Service Act, "but most of the risk pools aren't licensed as an insurance issuer in their state, so from a regulatory standpoint we're not equivalent to a commercial insurance product," says Amie Goldman, chair of the National Association of State Comprehensive Health Insurance Plans, an educational organization for the high-risk pools.

The preexisting-condition insurance plans are intended to serve as a bridge until 2014, when insurers won't be allowed to refuse coverage to people with medical problems or charge them more than other consumers.

Those affected include some of the 45,000 people who have enrolled in the new PCIPS established under the overhaul law, and the more than 220,000 who are in the generally pricier, old high-risk pools who can't join the new PCIPs because in order to qualify people have to be uninsured for six months.

It could be worse. Even though not required by law to eliminate such lifetime limits, some of the plans have opted against the caps anyway. Those PICPs includes the ones run by the federal government in 23 states and the District of Columbia. (The other 27 states run their own PCIPs.)

And in some states, officials have moved to lift limits on occasion. That's what happened in Kansas last year, where officials raised the lifetime limit in the state high-risk pool from $1 million to $3 million. Why? "We had people bumping up against the limit," says Sandy Praeger, the state's insurance commissioner.